It is generally known to a person skilled in the art of rolling bearing technology that the service life of a rolling bearing is considerably reduced by intruding fluids and dirt. Fluids and dirt of said type generally intrude into the rolling bearing when the rolling bearing is assembled in a dirty environment and above all when the rolling bearings are exposed to dirt, metal swarf and cooling liquids or the like during operation. Rolling bearings are exposed to a wide variety of impurities to a high degree in particular when they are used for mounting support rolls and working rolls on roll stands, so that a high degree of maintenance is required for the rolling bearings to achieve the intended service life of the bearing. One measure for reducing the maintenance expenditure and for increasing the service life of the bearing is therefore to suitably seal off the rolling bearings on roll stands of said type with respect to intruding fluids and dirt.
A sealed rolling bearing of said type is known generically from, for example, DE 199 35 014 A1. Said rolling bearing, which is embodied as a sealed four-row tapered roller bearing for support roll and working roll bearing arrangements on roll stands, is substantially composed of an axially multi-part outer bearing ring and an axially multi-part inner bearing ring as well as a number of rolling bodies which roll adjacent to one another in four rows between the bearing rings on the raceways thereof, with the rolling bodies of each row being held with uniform spacing relative to one another in the peripheral direction by means of in each case one bearing cage. The bearing space formed between the outer bearing ring and the inner bearing ring is sealed off with respect to intruding fluids and dirt at both axial ends by virtue of the inner bearing ring being formed at its axial end sections so as to be elongated relative to the axial end sections of the outer bearing ring, and by virtue of special sealing retainers being fitted on the elongated portions of the inner bearing ring, said sealing retainers having profiled ring seals and resting in each case against the axial end sections of the outer bearing ring. Said ring seals, embodied usually as metal-reinforced elastic radial shaft sealing rings, are on the one hand in each case fastened to the inner peripheral face of the sealing retainer and have, on the other hand, elastic sealing lips which extend to the inner bearing ring and are in sealing contact with the axially elongated end sections of the inner bearing ring and therefore hermetically seal off the bearing space formed between the outer bearing ring and the inner bearing ring.
In addition, it is also known from DE 42 06 764 A1 to design both the axial end sections of the inner bearing ring and the axial end sections of the outer bearing ring of a four-row tapered rolling bearing of said type to be elongated, and to fasten the ring seals, which are likewise embodied as radial shaft sealing rings, to the inner peripheral faces of the elongated portions of the outer bearing ring without special sealing retainers in such a way that the sealing lips of the radial shaft sealing rings slide on the cylinder faces of the elongated portions of the inner bearing ring.
However, a disadvantage of sealed rolling bearings of said type is that the elongated portions, which are provided specifically for sealing the rolling bearing, of the inner or also of the outer bearing ring increase the spatial requirement of the rolling bearing, and that rolling bearings which are sealed in this way must, for the same spatial requirement, be designed with lower load ratings than rolling bearings without seals, since the tapered rollers of the rolling bearings and their raceways must be of correspondingly smaller design as a result of the elongated portions. In addition to their relatively high costs, the known elastic radial shaft sealing rings have additionally proven to be disadvantageous in that, as a result of the frictional contact of their sealing lips against the cylinder faces of the elongated portions of the inner bearing ring, they are subject to an increased degree of wear and are therefore only suitable for providing sealing connections up to a certain speed limit. In addition, a failure in the cooling system of the roll stands can lead to a sudden temperature rise within the rolling bearing which goes beyond the temperature limit for elastic shaft sealing rings and therefore leads to damage to the radial shaft sealing rings, which lose their sealing function as a result.